Projection positioning system and projection positioning method thereof

ABSTRACT

A projection positioning system and a projection positioning method thereof are provided. A projection device projects a first test image and a second test image on a projection screen based on a projection range at different time points. At least one photosensitive element is disposed on the projection screen. In response to projecting the first test image, a computing device divides a first image sub-zone of the first test image according to the first image sub-zone corresponding to one of first optical parameters sensed by the photosensitive element, to generate the second test image. In response to projecting the second test image, the computing device determines positioning information of the photosensitive element with respect to the projection range according to a second image sub-zone corresponding to one of second optical parameters sensed by the photosensitive element. The projection device performs a projection adjustment function according to the positioning information.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serialno. 202010606452.X, filed on Jun. 29, 2020. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a projection technology, and in particular, toa projection positioning system and a projection positioning methodthereof.

2. Description of Related Art

A projector is a display device for generating large-size images. Animaging principle of the projector is to convert an illumination beamgenerated by a light source module into an image beam through a lightvalve device, and then project the image beam on a projection screen ora wall through a lens to form an image. With the advancement of aprojection technology and the reduction of manufacturing costs, theprojector is applied to various applications. In some applications, aboundary or a projection position of a projection image needs to beadjusted according to requirements of a projection environment. Forexample, in a touch projection system, a user needs to align and correctthe projection image of the projector and a touch zone provided by theprojection screen, so that the projector can correctly respond to atouch operation received by the touch projection screen to perform asubsequent action, and the user can smoothly interact with the touchprojection system. In detail, a touch boundary of the touch zone on theprojection screen needs to be accurately aligned with an image contentboundary in the projection image, so that the touch projection systemcan accurately provide a function that meets the user's expectation fora touch position of the touch operation.

In a traditional correction method, the projection system can position atarget projection position by shooting a projection result through acamera, but a camera parameter and camera correction together needs tobe considered in this method. Otherwise, the target projection boundarycannot be accurately positioned. Alternatively, in another traditionalcorrection method, the user can manually control movement of the imagecontent boundary in the projection image to position the targetprojection position. However, steps of the manual operation in thismanner are cumbersome and time-consuming, which is quite inconvenientfor the user.

The information disclosed in this Background section is only forenhancement of understanding of the background of the describedtechnology and therefore it may contain information that does not formthe prior art that is already known to a person of ordinary skill in theart. Further, the information disclosed in the Background section doesnot mean that one or more problems to be resolved by one or moreembodiments of the invention was acknowledged by a person of ordinaryskill in the art.

SUMMARY OF THE INVENTION

In view of the above, the invention provides a projection positioningsystem and a projection positioning method thereof, to efficiently andaccurately position image content in a projection image at a positiondefined by a photosensitive element.

An embodiment of the invention provides a projection positioning system,including a projection device, at least one photosensitive element, anda computing device. The projection device projects a first test imageand a second test image on a projection screen based on a projectionrange at different time points. The at least one photosensitive elementis disposed on the projection screen. The computing device is coupled tothe at least one photosensitive element and the projection device. Thefirst test image includes a plurality of first image sub-zones and thefirst image sub-zones respectively correspond to a plurality of firstoptical parameters. The second test image includes a plurality of secondimage sub-zones and the second image sub-zones respectively correspondto a plurality of second optical parameters. In response to projectingthe first test image by the projection device, the computing devicedivides the first image sub-zone according to the first image sub-zonecorresponding to one of the first optical parameters sensed by the atleast one photosensitive element, to generate the second test image. Inresponse to projecting the second test image by the projection device,the computing device determines positioning information of the at leastone photosensitive element with respect to the projection rangeaccording to the second image sub-zone corresponding to one of thesecond optical parameters sensed by the at least one photosensitiveelement. The projection device performs a projection adjustment functionaccording to the positioning information.

According to an embodiment, in the above projection positioning system,the projection adjustment function performed by the projection deviceaccording to the positioning information of the at least onephotosensitive element is to perform projection within a specificenclosed range surrounded by the at least one photosensitive element onthe projection screen, and the number of the at least one photosensitiveelement is greater than 1.

According to an embodiment, in the above projection positioning system,the projection adjustment function performed by the projection deviceaccording to the positioning information of the at least onephotosensitive element is to project a specific totem on a position ofthe at least one photosensitive element.

According to an embodiment, in the above projection positioning system,sizes of the second image sub-zones are smaller than sizes of the firstimage sub-zone.

According to an embodiment, in the above projection positioning system,in response to determining, by the computing device, that the sizes ofthe second image sub-zones conform to a minimum division unit, thecomputing device determines the positioning information of the at leastone photosensitive element with respect to the projection range.

According to an embodiment, in the above projection positioning system,the first image sub-zones and the second image sub-zones arerespectively arranged in a matrix, and the positioning informationincludes a first positioning position in a first axial direction and asecond positioning position in a second axial direction.

According to an embodiment, in the above projection positioning system,the first optical parameters and the second optical parameters include acolor sensing value or a brightness sensing value, and the at least onephotosensitive element includes a color sensor or a brightness sensor.

According to an embodiment, in the above projection positioning system,in response to projecting the first test image by the projection device,one of the first image sub-zones overlaps the at least onephotosensitive element, and the at least one photosensitive elementsenses one of the first optical parameters corresponding to one of thefirst image sub-zones.

According to an embodiment, in the above projection positioning system,in response to projecting the second test image by the projectiondevice, one of the second image sub-zones overlaps the at least onephotosensitive element, the at least one photosensitive element sensesone of the second optical parameters corresponding to one of the secondimage sub-zones, and the computing device determines the positioninginformation of the at least one photosensitive element with respect tothe projection range according to position information of one of thesecond image sub-zones in the second test image.

According to an embodiment, in the above projection positioning system,the projection device further projects a plurality of preset correctionimages respectively corresponding to a plurality of colors, and the atleast one photosensitive element sequentially senses a plurality ofcorrection sensing values when the projection device is projecting thepreset correction images, and obtains a sensing correction functionaccording to the correction sensing values, where the sensing correctionfunction is used to convert actual sensing values of the at least onephotosensitive element into the first optical parameters and the secondoptical parameters.

An embodiment of the invention provides a projection positioning method,including the following steps. A first test image is projected by aprojection device on a projection screen based on a projection range.The first test image includes a plurality of first image sub-zones andthe first image sub-zones respectively correspond to a plurality offirst optical parameters. The first image sub-zone is divided accordingto the first image sub-zone corresponding to one of the first opticalparameters sensed by the at least one photosensitive element, inresponse to the first test image projected by the projection device,parameter, to generate the second test image.

The second test image is projected by the projection device on theprojection screen based on the projection range. The second test imageincludes a plurality of second image sub-zones and the second imagesub-zones respectively correspond to a plurality of second opticalparameters. Positioning information of the at least one photosensitiveelement with respect to the projection range is determined according tothe second image sub-zone corresponding to one of the second opticalparameters sensed by the at least one photosensitive element, inresponse to the second test image projected by the projection device. Aprojection adjustment function is performed according to the positioninginformation.

According to an embodiment, in the above projection positioning method,the step of performing a projection adjustment function according to thepositioning information includes the following step. Projection within aspecific enclosed range surrounded by the at least one photosensitiveelement on the projection screen is performed by the projection deviceaccording to the positioning information of the at least onephotosensitive element, and the number of the at least onephotosensitive element is greater than 1.

According to an embodiment, in the above projection positioning method,the step of performing a projection adjustment function according to thepositioning information includes the following step. A specific totem ona position of the at least one photosensitive element is projected bythe projection device according to the positioning information of the atleast one photosensitive element.

According to an embodiment, in the above projection positioning method,sizes of the second image sub-zones are smaller than sizes of the firstimage sub-zone.

According to an embodiment, in the above projection positioning method,the step of determining, in response to projecting the second test imageby the projection device, positioning information of the at least onephotosensitive element with respect to the projection range according tothe second sub-image corresponding to one of the second opticalparameters sensed by the at least one photosensitive element includesthe following step. The positioning information of the at least onephotosensitive element with respect to the projection range isdetermined in response to determining that the sizes of the second imagesub-zones conform to a minimum division unit.

According to an embodiment, in the above projection positioning method,the first image sub-zones and the second image sub-zones arerespectively arranged in a matrix, and the positioning informationincludes a first positioning position in a first axial direction and asecond positioning position in a second axial direction.

According to an embodiment, in the above projection positioning method,the first optical parameters and the second optical parameters include acolor sensing value or a brightness sensing value, and the at least onephotosensitive element includes a color sensor or a brightness sensor.

According to an embodiment, in the above projection positioning method,in response to projecting the first test image by the projection device,one of the first image sub-zones overlaps the at least onephotosensitive element, and the at least one photosensitive elementsenses one of the first optical parameters corresponding to one of thefirst image sub-zones.

According to an embodiment, in the above projection positioning method,in response to projecting the second test image by the projectiondevice, one of the second image sub-zones overlaps the at least onephotosensitive element, and the at least one photosensitive elementsenses one of the second optical parameters corresponding to one of thesecond image sub-zones; and the step of determining the positioninginformation of the at least one photosensitive element with respect tothe projection range includes the following step. The positioninginformation of the at least one photosensitive element with respect tothe projection range is determined according to position information ofone of the second image sub-zones in the second test image.

According to an embodiment, in the above projection positioning method,the method further includes the following steps. A plurality of presetcorrection images respectively corresponding to a plurality of colorsare projected by a projection device. A plurality of correction sensingvalues when the preset correction images are being projected aresequentially sensed by the at least one photosensitive element to obtaina sensing correction function according to the correction sensingvalues. The sensing correction function is used to convert actualsensing values of the at least one photosensitive element into the firstoptical parameters and the second optical parameters.

Based on the above, in the embodiments of the invention, the projectiondevice projects a plurality of test images on the projection screen atdifferent time points, and the test images each include a plurality ofimage sub-zones corresponding to different optical parameters. Positionsand sizes of the image sub-zones in these test images change as the testimages are switched. When the projection device sequentially projectsthese test images on the projection screen, the photosensitive elementsdisposed on the projection screen sequentially sense optical parameterscorresponding to an image sub-zone in each test image. Herein, theprojection positioning system determines a position of an image sub-zonein a next test image according to a sensing result of the photosensitiveelement for a current test image. Because the positions and sizes of theimage sub-zones change as the test images are switched, the positioninginformation of the photosensitive element with respect to the projectionrange can be obtained according to the sensed optical parameter, toadjust projection content according to the positioning information ofthe photosensitive element. In this way, an efficient and convenientprojection positioning method can be provided, thereby greatly improvingthe operation convenience of the projection device.

Other objectives, features and advantages of the present invention willbe further understood from the further technological features disclosedby the embodiments of the present invention wherein there are shown anddescribed preferred embodiments of this invention, simply by way ofillustration of modes best suited to carry out the invention.

In order to make the foregoing features and advantages of the inventionmore apparent and easier to understand, detailed description areprovided below by listing embodiments with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic diagram of a projection positioning systemaccording to an embodiment of the invention.

FIG. 2 is a flowchart of a projection positioning method according to anembodiment of the invention.

FIG. 3A is an example of a first test image according to an embodimentof the invention.

FIG. 3B is an example of a second test image according to the embodimentof FIG. 3A.

FIG. 4A and FIG. 4B are schematic diagrams of a projection positioningmethod according to an embodiment of the invention.

FIG. 5 is an example of positioning a photosensitive element accordingto an image sub-zone according to an example of FIG. 4.

DESCRIPTION OF THE EMBODIMENTS

It is to be understood that other embodiment may be utilized andstructural changes may be made without departing from the scope of theinvention. Also, it is to be understood that the phraseology andterminology used herein are for the purpose of description and shouldnot be regarded as limiting. The use of “including,” “comprising,” or“having” and variations thereof herein is meant to encompass the itemslisted thereafter and equivalents thereof as well as additional items.Unless limited otherwise, the terms “connected,” “coupled,” and“mounted,” and variations thereof herein are used broadly and encompassdirect and indirect connections, couplings, and mountings.

Some embodiments of the invention are described below in detail withreference to the accompanying drawings. Reference numerals referenced inthe following description are regarded as identical or similar elementswhen identical reference numerals appear in different drawings. Theembodiments are merely some of the embodiments of the invention, and donot disclose all the implementations of the invention. More precisely,the embodiments are merely examples of the system and method in theclaims of the invention.

FIG. 1 is a schematic diagram of a projection positioning systemaccording to an embodiment of the invention. Referring to FIG. 1, aprojection positioning system 10 includes a projection device 110, atleast one photosensitive element, a projection screen S1, and acomputing device 130. An example in which four photosensitive elements120_1-120_4 are disposed is used for description below, or only onephotosensitive element may be disposed.

The projection device 110 may project an image on the projection screenS1, and may be a liquid crystal projector (LCP), a digital lightprocessing (DLP) projector, a liquid crystal on silicon (LCOS)projection display device, or the like. In the embodiment, theprojection device 110 may further include a light source module, anoptomechanical module, a lens module, a related optical element, acircuit control element, and the like. For example, the projectiondevice 110 may further include an image processing circuit forperforming image processing. In an embodiment, the projection device 110may sequentially project a plurality of test images (a first test imageand a second test image) on the projection screen S1 based on aprojection range R1 at different time points. The projection range R1depends on factors such as a distance between the projection device 110and the projection screen S1, a projection direction of the projectiondevice 110, and an optical characteristic of an internal opticalelement.

The projection screen S1 is configured to display a projection imageprojected by the projection device 110. In an embodiment, the projectionscreen S1 has a frame F1. In an embodiment, the touch-type projectionscreen Si may include a frame F1 and a touch panel embedded in the frameF1. The touch-type projection screen S1 may display the projection imageaccording to an image beam projected by the projection device 110 anddetect a touch operation issued by a user. Alternatively, in anembodiment, the projection screen S1 may include a frame F1 and otherdisplay media embedded in the frame F1 and having no touch function,such as a projection screen or a whiteboard embedded in the frame F1 andformed by the frame F1. However, although FIG. 1 illustrates theprojection screen S1 including the frame F1 as an example, the inventionis not limited thereto. In other embodiments, the projection screen S1may not include a frame.

The photosensitive elements 120_1-120_4 are disposed on the projectionscreen S1. The photosensitive elements 120_1-120_4 may be configured tosense an optical parameter of the projection image. The photosensitiveelements 120_1-120_4 may include a color sensor or a brightness sensor.The photosensitive elements 120_1-120_4 may be, for example, a chargecoupled device (CCD), a complementary metal-oxide semiconductor (CMOS)device, or other devices. In an embodiment, the photosensitive elements120_1-120_4 are respectively located at a plurality of corners of theframe F1 of the projection screen S1, and the projection range R1 of theprojection device 110 at least covers the frame F1. Alternatively, inother embodiments, the photosensitive elements 120_1-120_4 may berespectively located at a plurality of specific positions within theframe F1 of the projection screen S1, and the projection range R1 of theprojection device 110 covers the photosensitive elements 120_1-120_4 onthe projection screen S1.

However, it should be noted that in FIG. 1, there are fourphotosensitive elements 120_1-120_4 and the photosensitive elements arerespectively located at four corners of the frame F1 of the projectionscreen S1. However, the number and disposing positions of thephotosensitive elements are not limited in the invention, and may be setaccording to actual requirements. For example, the number ofphotosensitive elements may be other numbers, such as 1, 2, or 8. In anembodiment, in order to obtain a rectangular boundary defined by theframe F1 according to a sensing result generated by the photosensitiveelement, there are at least two photosensitive elements and thephotosensitive elements are respectively located at two corners of adiagonal line of the frame F1. In an embodiment, in order to project aspecific pattern to a specific position in the projection image, thereis at least one photosensitive element.

The computing device 130 is coupled to the projection device 110 and theplurality of photosensitive elements 120_1-120_4, and includes a memoryand at least one processor coupled to the memory. The computing device130 may be a computer control system with a computing capability, suchas a desktop computer, a notebook computer, a work station, anindustrial computer, or a server host. The memory may be any type ofnon-transitory, volatile, and non-volatile data storage device, and isconfigured to store buffered data, permanent data, and compiled code forperforming a function of the computing device 130. The processor may bea field programmable gate array (FPGA), a programmable logic device(PLD), an application-specific integrated circuit (ASIC), or othersimilar devices or a combination of these devices. The processor may bea central processing unit (CPU), a programmable general-purpose orspecial-purpose microprocessor (microprocessor), a digital signalprocessor (DSP), a graphics processing unit (GPU), other similar devicesor a combination of these devices.

In an embodiment, the projection device 110 is controlled to project aplurality of designed test images and the photosensitive elements120_1-120_4 are disposed on the projection screen S1 for sensing, andthe computing device 130 may obtain positioning information of thephotosensitive elements 120_1-120_4 in the projection range R1 accordingto sensing results reported by the photosensitive elements 120_1-120_4.In this way, the projection device 110 may perform a projectionadjustment function according to the positioning information of thephotosensitive elements 120_1-120_4, such as aligning a boundary ofprojection content with the frame F1 or projecting a specific totem on aspecific position. Examples will be listed below for detaileddescription.

FIG. 2 is a flowchart of a projection positioning method according to anembodiment of the invention. The procedure of the method in FIG. 2 maybe implemented by each element of the projection positioning system 10in FIG. 1. Referring to both FIG. 1 and FIG. 2, steps of the projectionpositioning method in the embodiment are described below with theelements of the projection positioning system 10 in FIG. 1.

It should be noted that the projection device 110 may project a firsttest image and a second test image on the projection screen S1 atdifferent time points. The first test image includes a plurality offirst image sub-zones corresponding to different first opticalparameters, and the second test image includes a plurality of secondimage sub-zones corresponding to a plurality of second opticalparameter. The first optical parameter and the second optical parametermay include a color sensing value or a brightness sensing value. Forexample, the first optical parameter and the second optical parametermay be a grayscale value or a color channel value (for example, an RGBchannel value). When the photosensitive elements 120_1-120_4 are colorsensors, the first optical parameter and the second optical parameterare color sensing values. When the photosensitive elements 120_1-120_4are brightness sensors, the first optical parameter and the secondoptical parameter are brightness sensing values. Herein, the pluralityof second image sub-zones in the second test image are generated byselecting one of the first image sub-zones for division, and thecomputing device 130 may determine the divided first image sub-zoneaccording to sensing results of the photosensitive elements 120_1-120_4.For clarity, the following procedure in FIG. 2 takes positioning of thephotosensitive element 120_1 first as an example.

In step S201, the projection device 110 projects the first test image onthe projection screen S1 based on a projection range R1. The projectiondevice 110 projects an image beam on the projection screen S1, and thefirst test image projected by the projection device 110 in theprojection range R1 covers the photosensitive element 120_1. Inaddition, the first test image includes the plurality of first imagesub-zones, the first image sub-zones respectively correspond to aplurality of first optical parameters, and the first optical parametersare different from each other.

For example, FIG. 3A is an example of a first test image according to anembodiment of the invention. Referring to FIG. 3A, a first test imageIt1 may be a grayscale image or a color image, and may include fourfirst image sub-zones SZ1-SZ4. The first image sub-zones SZ1-SZ4 may bearranged in a matrix, that is, four rectangular blocks arranged in amatrix of two columns and two rows (2×2). The first image sub-zonesSZ1-SZ4 respectively correspond to different first optical parameters.In detail, the first test image It1 may include four the first imagesub-zones SZ1-SZ4 respectively corresponding to four colors or fourgrayscale values. For example, the first image sub-zone SZ1 maycorrespond to an RGB channel value (0, 0, 0) and be presented as a blackblock. The first image sub-zone SZ2 may correspond to an RGB channelvalue (255, 0, 0) and be presented as a red block. The first imagesub-zone SZ3 may correspond to an RGB channel value (0, 255, 0) and bepresented as a green block. The first image sub-zone SZ4 may correspondto an RGB channel value (0, 0, 255) and be presented as a blue block.

Alternatively, the first image sub-zones SZ1-SZ4 may respectivelycorrespond to different four grayscale values and be presented as fourgrayscale blocks with different depths.

It should be noted that in FIG. 3A, in response to projecting the firsttest image It1 on the projection screen S1 by the projection device 110,one (the first image sub-zone SZ1) of the first image sub-zones SZ1-SZ4overlaps the photosensitive element 120_1, and the photosensitiveelement 120_1 senses one of the first optical parameters correspondingto one (the first image sub-zone SZ1) of the first image sub-zonesSZ1-SZ4. For example, assuming that the first image sub-zone SZ1corresponds to the RGB channel value (0, 0, 0) and is presented as ablack block, the first optical parameter sensed by the photosensitiveelement 120_1 is the RGB channel value (0, 0, 0).

However, the first test image It1 in FIG. 3A is only an exemplarydescription, and is not intended to limit the invention. The number andarrangement manners of the first image sub-zones and respectivecorresponding first optical parameters may be configured according toactual requirements. For example, in other embodiments, the first testimage It1 may include nine first image sub-zones arranged in a matrix ofthree columns and three rows (3×3), or the first test image It1 mayinclude two first image sub-zones arranged in a matrix of one column andtwo rows (1×2).

In step S202, in response to projecting the first test image by theprojection device 110, the computing device 130 divides the first imagesub-zone according to the first image sub-zone corresponding to one ofthe first optical parameters sensed by the photosensitive element 120_1,to generate the second test image. In detail, when the projection device110 projects the first test image, because the photosensitive element120_1 is located in one of the first image sub-zones, the photosensitiveelement 120_1 may sense the first optical parameter corresponding to oneof the first image sub-zones. In other words, according to the opticalparameter sensed by the photosensitive element 120_1, the computingdevice 130 may select the first image sub-zone corresponding to thephotosensitive element 120_1 for division to generate the second testimage.

The computing device 130 divides the first image sub-zone correspondingto the photosensitive element 120_1 to generate the plurality of secondimage sub-zones in the second test image. It can be learned that a rangeof the second image sub-zones in the second test image corresponds to arange of the first image sub-zones in the first test image correspondingto the photosensitive element 120_1, the second test image also includesthe plurality of second image sub-zones, and these second imagesub-zones respectively correspond to a plurality of second opticalparameters.

For example, FIG. 3B is an example of a second test image according tothe embodiment of FIG. 3A. Referring to FIG. 3A and FIG. 3B, in responseto sensing the first optical parameter corresponding to the first imagesub-zone SZ1 by the sensing element 120_1, the computing device 130divides the first image sub-zone SZ1 to generate a second test imageIt2. Referring to FIG. 3B, the second test image It2 may be a grayscaleimage or a color image and may include four second image sub-zonesSZ5-SZ8, and a range of the four second image sub-zones SZ5-SZ8corresponds to a range of the first image sub-zone SZ1 in the first testimage It1. The second image sub-zones SZ5-SZ8 may be arranged in amatrix, that is, four rectangular blocks arranged in a 2x2 matrix. Thesecond image sub-zones SZ5-SZ8 correspond to different second opticalparameters, that is, the second test image It2 may include four secondimage sub-zones SZ5-SZ8 respectively corresponding to four colors orfour grayscale values. In other words, the computing device 130 dividesthe first image sub-zone SZ1 to generate the four second image sub-zonesSZ5-SZ8 in the second test image It2. Sizes of the second imagesub-zones SZ5-SZ8 in the second test image It2 are smaller than sizes ofthe first image sub-zones SZ1-SZ4 in the first test image It1. In thisexample, assuming that the sizes of the first image sub-zones SZ1-SZ4are M×N (unit pixels), the sizes of the second image sub-zones SZ5-SZ8are M/2×N/2.

However, the second test image It2 in FIG. 3B is only an exemplarydescription, and is not intended to limit the invention. The number andarrangement manners of the second image sub-zones and respectivecorresponding second optical parameters may be configured according toactual requirements. In addition, the number of second image sub-zonesin the second test image may be the same or different from that of thefirst image sub-zones in the first test image, which is not limited inthe invention. In addition, the second optical parameter correspondingto the second image sub-zone may be the same or different from the firstoptical parameter corresponding to the first image sub-zone, which isnot limited in the invention.

In step S203, the projection device 110 projects the second test imageon the projection screen S1 based on the projection range R1. Then, instep S204, in response to projecting the second test image on theprojection screen S1 by the projection device 110, the computing device130 determines positioning information of the photosensitive element120_1 with respect to the projection range according to the second imagesub-zone corresponding to one of the second optical parameters sensed bythe at least one photosensitive element 120_1. For example, referring toFIG. 3B, in response to projecting the second test image It2 by theprojection device 110, one (the second image sub-zone SZ5) of the secondimage sub-zones SZ5-SZ8 overlaps the photosensitive element 120_1, thephotosensitive element 120_1 senses one of the second optical parameterscorresponding to one (the second image sub-zone SZ5) of the second imagesub-zones SZ5-SZ8, and the computing device 130 may determine thepositioning information of the photosensitive element 120_1 with respectto the projection range R1 according to position information of one (thesecond image sub-zone SZ5) of the second image sub-zones SZ5-SZ8 in thesecond test image It2.

Based on this, according to the second optical parameter sensed by thephotosensitive element 120_1 when the projection device 110 projects thesecond test image It2, the computing device 130 may determine that thephotosensitive element 120_1 is located in a specified second imagesub-zone, and then position the photosensitive element 120_1 accordingto pixel position information of the second image sub-zone. Thecomputing device 130 may determine the positioning information of thephotosensitive element 120_1 according to pixel position information ina specified second image sub-zone. It can be learned that if a size ofthe second image sub-zone is smaller, the computing device 130 canobtain a more accurate positioning result. The positioning informationof the photosensitive element 120_1 may include a pixel coordinate or apositioning zone.

In an embodiment, the computing device 130 may repeatedly divide animage sub-zone to generate a next test image to more accurately obtain apositioning result of the photosensitive element 120_1 with respect tothe projection range according to a smaller image sub-zone. Therefore,in an embodiment, the computing device 130 may determine whether thesize of the second image sub-zone conforms to a minimum division unit,and the minimum division unit is, for example, 1×1 pixel or a×b pixels.In response to determining, by the computing device 130, that the sizeof the second image sub-zone meets a minimum division unit, thecomputing device 130 may determine the positioning information of thephotosensitive element 120_1 with respect to the projection range R1according to a sensing result of the photosensitive element 120_1. Forexample, when the size of the second image sub-zone is a×b pixels, thecomputing device 130 may use one pixel position in the second imagesub-zone corresponding to the sensing result as the positioninginformation of the photosensitive element 120_1. Alternatively, when thesize of the second image sub-zone is 1×1 pixel, the computing device 130may use a unique pixel position in the second image sub-zonecorresponding to the sensing result as the positioning information ofthe photosensitive element 120_1. Alternatively, when the size of thesecond image sub-zone is a×b pixels, the computing device 130 maystatistically compute the positioning information of the photosensitiveelement 120_1 according to four pixel positions at four corners of thesecond image sub-zone corresponding to the sensing result.

It should be noted that, based on the same principle and process, thecomputing device 130 may also obtain positioning information of otherphotosensitive elements 120_2 to 120_4. Finally, in step S205, theprojection device 110 performs a projection adjustment functionaccording to the positioning information of the one or morephotosensitive elements 120_1-120_4. In other words, the projectiondevice 110 may adjust projection content or a projection parameteraccording to the positioning information of the photosensitive elements120_1-120_4. In an embodiment, the projection adjustment functionperformed by the projection device 110 according to the positioninginformation of the photosensitive elements 120_1-120_4 is to performprojection within a specific enclosed range surrounded by thephotosensitive elements 120_1-120_4 on the projection screen S1. Basedon this, when the photosensitive elements 120_1-120_4 are disposed onfour corner of the frame F1, the projection device 110 may obtain anideal display boundary defined by the frame F1 in the projection rangeR1 according to the positioning information of the photosensitiveelements 120_1-120_4, and adjust projection content (for example, imagezoom processing or keystone correction) accordingly, so that theprojection content can be aligned with the frame F1.

It should be noted that in FIG. 1, for example, the photosensitiveelements 120_1-120_4 are arranged in a rectangle. Therefore, theprojection device 110 may perform projection within a rectangular rangeaccording to the positioning information of the photosensitive elements120_1-120_4. In other embodiments, assuming that the plurality ofphotosensitive elements are arranged in an octagonal shape, theprojection device 110 may perform projection within an octagonal rangeaccording to positioning information of eight photosensitive elements.

Alternatively, in an embodiment, the projection adjustment functionperformed by the projection device 110 according to positioninginformation of the single photosensitive element 120_1 is to project aspecific totem on a position of the photosensitive element 120_1. Forexample, a user may dispose one photosensitive element at a specificposition on the projection screen S1, and after the computing device 130obtains the positioning information of the photosensitive element, theprojection device 110 may anchor and project a manufacturer logo, anadvertising logo, or other preset totems according to positioningposition of the photosensitive element, that is, the specific totem inthe image projected by the projection device 10 covers thephotosensitive element.

Based on the above description, it can be learned that positions andsizes of image sub-zones in a plurality of test images projected by theprojection device 110 vary. In other words, when the projection device110 projects the second test image after projecting the first testimage, positions and sizes of a plurality of image sub-zonescorresponding to different optical parameters change. For example, sizesof the four first image sub-zones SZ1-SZ4 in the first test image It1 ofFIG. 3A are respectively a quarter of the first test image It1, andsizes of the four second image sub-zones SZ5-SZ8 in the first test imageIt2 of FIG. 3B are respectively quarters of corresponding first imagesub-zones. However, the invention is not limited thereto. By graduallyreducing a size of an image sub-zone in each test image and adjusting aposition of the image sub-zone, the computing device 130 may obtain thepositioning information of the photosensitive element according to theoptical parameter sensed by the photosensitive element.

In order to explain the principle of the invention in more detail, FIG.4A and FIG. 4B are schematic diagrams of a projection positioning methodaccording to an embodiment of the invention. Referring to FIG. 4A andFIG. 4B, in this example, estimation of positioning information of onephotosensitive element 120_1 is used as an example for description, butthe same principle may be implemented to position a plurality ofphotosensitive elements. In addition, in FIG. 4A and FIG. 4B, forexample, the number of image sub-zones generated during each division isequal to 4 and optical parameters are a black RGB channel value, a redRGB channel value, a green RGB channel value, and a blue RGB channelvalue. However, the invention is not limited thereto.

Referring to FIG. 4A, a test image It3 may include four image sub-zonesSZ9-SZ12 arranged in a matrix, and the image sub-zones SZ9-SZ12correspond to different RGB channel values and are respectivelypresented in black, red, green, and blue. In other words, the projectiondevice 110 projects the image sub-zone SZ9 according to an RGB channelvalue (0, 0, 0); the projection device 110 projects the image sub-zoneSZ10 according to an RGB channel value (255, 0, 0); the projectiondevice 110 projects the image sub-zone SZ11 according to an RGB channelvalue (0, 255, 0); and the projection device 110 projects the imagesub-zone SZ12 according to an RGB channel value (0, 0, 255).

When the test image It3 is projected at a time point t1, because thephotosensitive element 120_1 is located within the image sub-zone SZ9,the photosensitive element 120_1 may sense an optical parameter (a blackRGB channel value) corresponding to the image sub-zone SZ9.Correspondingly, according to a sensing result reported by thephotosensitive element 120_1, the computing device 130 may learn thatthe photosensitive element 120_1 is within coverage of the imagesub-zone SZ9. Therefore, the computing device 130 may divide the imagesub-zone SZ9 to generate image sub-zones SZ13-SZ16 in a next test imageIt4. Similarly, the test image It4 may include four image sub-zonesSZ13-SZ16 arranged in a matrix, and the image sub-zones SZ13-SZ16correspond to different RGB channel values and are respectivelypresented in black, red, green, and blue.

Referring to FIG. 4A and FIG. 4B, when the test image It4 is projectedat a time point t2, because the photosensitive element 120_1 is locatedwithin the image sub-zone SZ13, the photosensitive element 120_1 maysense an optical parameter (a black RGB channel value) corresponding tothe image sub-zone SZ13. Correspondingly, according to a sensing resultreported by the photosensitive element 120_1, the computing device 130may learn that the photosensitive element 120_1 is within coverage ofthe image sub-zone SZ13. Therefore, the computing device 130 may dividethe image sub-zone SZ13 to generate image sub-zones SZ17-SZ20 in a nexttest image It5. Similarly, the test image It5 may include four imagesub-zones SZ17-SZ20 arranged in a matrix, and the image sub-zonesSZ17-SZ20 correspond to different RGB channel values and arerespectively presented in black, red, green, and blue.

Referring to FIG. 4B, when the test image It5 is projected at a timepoint t3, because the photosensitive element 120_1 is located within theimage sub-zone SZ19, the photosensitive element 120_1 may sense anoptical parameter (a green RGB channel value) corresponding to the imagesub-zone SZ19. Correspondingly, according to a sensing result reportedby the photosensitive element 120_1, the computing device 130 may learnthat the photosensitive element 120_1 is within coverage of the imagesub-zone SZ19. Therefore, the computing device 130 may divide the imagesub-zone SZ19 to generate image sub-zones in a next test image.

By analogy, by repeatedly dividing an image sub-zone according to asensing result and sequentially projecting a plurality of test images,position information of a gradually reduced image sub-zone graduallyapproaches a true position of a photosensitive element in a projectionimage. It should be noted that, in this example, the computing device130 may determine whether a size of an image sub-zone conforms to aminimum division unit, and the minimum division unit may be 3×2 pixels.When a test image Itn is projected at a time point tn, according to asensing result (a blue RGB channel value) reported by the photosensitiveelement 120_1, the computing device 130 may learn that thephotosensitive element 120_1 is located in coverage of an image sub-zoneSZT. In response to determining, by the computing device 130, that asize of the image sub-zone SZT conforms to the minimum division unit(3×2 pixels), the computing device 130 may determine the positioninginformation of the photosensitive element 120_1 with respect to theprojection range R1 according to a pixel position in the image sub-zoneSZT. The positioning information may include a first positioningposition in a first axial direction (X axis) and a second positioningposition in a second axial direction (Y axis), that is, the positioninginformation of the photosensitive element 120_1 may be pixel coordinates(X1, Y1). For example, referring to FIG. 5, FIG. 5 is an example ofpositioning a photosensitive element according to an image sub-zoneaccording to an example of FIG. 4. The computing device 130 may obtainthe pixel position (X1, Y1) of one pixel P1 in the image sub-zone SZT asthe positioning information of the photosensitive element 120_1.

It should be noted that when the projection device 110 performsprojection in different environments, a color and brightness presentedon the projection screen S1 vary due to the different environments.Therefore, in order to ensure that the computing device 130 can learn ofa positioning position of the photosensitive element according to abrightness sensing result or a color sensing result of thephotosensitive element, in an embodiment, the projection positioningsystem 10 may perform a sensing value correction procedure beforepositioning the position of the photosensitive element. In other words,in an embodiment, the projection device 110 further sequentiallyprojects a plurality of preset correction images respectivelycorresponding to a plurality of colors. In detail, the projection device120 may sequentially project a plurality of preset correction imagescorresponding to different grayscale values, or sequentially project aplurality of preset correction images corresponding to different RGBchannel values. The photosensitive elements 120_1-120_4 may sequentiallysense a plurality of correction sensing values when the projectiondevice 110 projects the preset correction images, and obtain a sensingcorrection function according to the correction sensing values. Thesensing correction function is used to convert actual sensing values ofthe photosensitive elements 120_1-120_4 into corresponding opticalparameters (the first optical parameter and the second opticalparameter), and the sensing correction function may be implemented as alook-up table or a mathematical function, which is not limited in theinvention. In other words, the computing device 130 may convert theactual sensing values of the photosensitive elements 120_1-120_4 intothe first optical parameter and the second optical parameter accordingto the sensing correction function, to facilitate subsequentdetermination of positions of the photosensitive elements 120_1-120_4.In other embodiments, during the sensing value correction procedure,only one photosensitive element 120_1 is required to sense the presetcorrection images projected by the projection device 110 in sequence andobtain the plurality of correction sensing values, and then the sensingcorrection function is obtained based on the correction sensing value.The invention does not limit the number of photosensitive elements usedfor sensing during the sensing value correction procedure.

It can be seen that, through the sensing value correction procedure ofthe projection positioning system 10, in addition to determining whetherthe projection range R1 of the projection device 110 covers thephotosensitive elements 120_1-120_4, the computing device 130 mayconvert actual sensing values measured in an actual projectionenvironment into optical parameters corresponding to each imagesub-zone. For example, in the examples of FIG. 4A and FIG. 4B, theoptical parameters of each image sub-zone respectively correspond tofour groups of RGB channel values of black, red, green, and blue.Therefore, in the sensing value correction procedure, the projectiondevice 110 sequentially project four preset correction imagescorresponding to an RGB channel value (0, 0, 0), an RGB channel value(255, 0, 0), an RGB channel value (0, 255, 0), and an RGB channel value(0, 0, 255). Based on this, when the projection device 110 projects ablack preset correction image, the computing device 130 may obtain acorrection sensing value V1 corresponding to the RGB channel value (0,0, 0) according to the correction sensing values sensed by thephotosensitive elements 120_1 to 120_4. When the projection device 110projects a red preset correction image, the computing device 130 mayobtain a correction sensing value V2 corresponding to the RGB channelvalue (255, 0, 0) according to the correction sensing values sensed bythe photosensitive elements 120_1 to 120_4. When the projection device110 projects a green preset correction image, the computing device 130may obtain a correction sensing value V3 corresponding to the RGBchannel value (0, 255, 0) according to the correction sensing valuessensed by the photosensitive elements 120_1 to 120_4. When theprojection device 110 projects a blue preset correction image, thecomputing device 130 may obtain a correction sensing value V4corresponding to the RGB channel value (0, 0, 255) according to thecorrection sensing values sensed by the photosensitive elements 120_1 to120_4.

Therefore, the computing device 130 may generate a correction look-uptable based on the correction sensing values V1-V4, and determine anoptical parameter sensed by the photosensitive element in a positioningprocess according to the correction look-up table. Through the sensingvalue correction procedure of the projection positioning system 10, theprojection device 110 can accurately perform the projection positioningmethod in different environments.

In view of the above, in the embodiment of the invention, because theuser does not need to manually correct a projection image and does notneed to consider a camera parameter and camera correction, a moreconvenient and fast projection positioning method is provided. Bygradually dividing an image sub-zone and using the photosensitiveelement to sense the optical parameter, the positioning information ofthe photosensitive element can be accurately obtained, thereby furtherimproving the display quality and the use convenience of the projectiondevice. Furthermore, other objectives and advantages of the inventionmay further be learned from technical features disclosed in theinvention.

The foregoing description of the preferred embodiments of the inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform or to exemplary embodiments disclosed. Accordingly, the foregoingdescription should be regarded as illustrative rather than restrictive.Obviously, many modifications and variations will be apparent topractitioners skilled in this art. The embodiments are chosen anddescribed in order to best explain the principles of the invention andits best mode practical application, thereby to enable persons skilledin the art to understand the invention for various embodiments and withvarious modifications as are suited to the particular use orimplementation contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto and their equivalentsin which all terms are meant in their broadest reasonable sense unlessotherwise indicated. Therefore, the term “the invention”, “the presentinvention” or the like does not necessarily limit the claim scope to aspecific embodiment, and the reference to particularly preferredexemplary embodiments of the invention does not imply a limitation onthe invention, and no such limitation is to be inferred. The inventionis limited only by the spirit and scope of the appended claims.Moreover, these claims may refer to use “first”, “second”, etc.following with noun or element. Such terms should be understood as anomenclature and should not be construed as giving the limitation on thenumber of the elements modified by such nomenclature unless specificnumber has been given. The abstract of the disclosure is provided tocomply with the rules requiring an abstract, which will allow a searcherto quickly ascertain the subject matter of the technical disclosure ofany patent issued from this disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Any advantages and benefits described may notapply to all embodiments of the invention. It should be appreciated thatvariations may be made in the embodiments described by persons skilledin the art without departing from the scope of the present invention asdefined by the following claims. Moreover, no element and component inthe present disclosure is intended to be dedicated to the publicregardless of whether the element or component is explicitly recited inthe following claims.

What is claimed is:
 1. A projection positioning system, comprising: aprojection device, configured to project a first test image and a secondtest image on a projection screen based on a projection range atdifferent time points; at least one photosensitive element, disposed onthe projection screen; and a computing device, coupled to the at leastone photosensitive element and the projection device, wherein the firsttest image comprises a plurality of first image sub-zones and the firstimage sub-zones respectively correspond to a plurality of first opticalparameters, and the second test image comprises a plurality of secondimage sub-zones and the second image sub-zones respectively correspondto a plurality of second optical parameters; in response to projectingthe first test image by the projection device, the computing devicedivides the first image sub-zone according to the first image sub-zonecorresponding to one of the first optical parameters sensed by the atleast one photosensitive element, to generate the second test image; andin response to projecting the second test image by the projectiondevice, the computing device determines positioning information of theat least one photosensitive element with respect to the projection rangeaccording to the second image sub-zone corresponding to one of thesecond optical parameters sensed by the at least one photosensitiveelement, and the projection device performs a projection adjustmentfunction according to the positioning information.
 2. The projectionpositioning system according to claim 1, wherein the projectionadjustment function performed by the projection device according to thepositioning information of the at least one photosensitive element is toperform projection within a specific enclosed range surrounded by the atleast one photosensitive element on the projection screen, and thenumber of the at least one photosensitive element is greater than
 1. 3.The projection positioning system according to claim 1, wherein theprojection adjustment function performed by the projection deviceaccording to the positioning information of the at least onephotosensitive element is to project a specific totem on a position ofthe at least one photosensitive element.
 4. The projection positioningsystem according to claim 1, wherein sizes of the second image sub-zonesare smaller than sizes of the first image sub-zone.
 5. The projectionpositioning system according to claim 4, wherein in response todetermining, by the computing device, that the sizes of the second imagesub-zones conform to a minimum division unit, the computing devicedetermines the positioning information of the at least onephotosensitive element with respect to the projection range.
 6. Theprojection positioning system according to claim 1, wherein the firstimage sub-zones and the second image sub-zones are respectively arrangedin a matrix, and the positioning information comprises a firstpositioning position in a first axial direction and a second positioningposition in a second axial direction.
 7. The projection positioningsystem according to claim 1, wherein the first optical parameters andthe second optical parameters comprise a color sensing value or abrightness sensing value, and the at least one photosensitive elementcomprises a color sensor or a brightness sensor.
 8. The projectionpositioning system according to claim 1, wherein in response toprojecting the first test image by the projection device, one of thefirst image sub-zones overlaps the at least one photosensitive element,and the at least one photosensitive element senses one of the firstoptical parameters corresponding to one of the first image sub-zones. 9.The projection positioning system according to claim 1, wherein inresponse to projecting the second test image by the projection device,one of the second image sub-zones overlaps the at least onephotosensitive element, the at least one photosensitive element sensesone of the second optical parameters corresponding to one of the secondimage sub-zones, and the computing device determines the positioninginformation of the at least one photosensitive element with respect tothe projection range according to position information of one of thesecond image sub-zones in the second test image.
 10. The projectionpositioning system according to claim 1, wherein the projection devicefurther projects a plurality of preset correction images respectivelycorresponding to a plurality of colors, and the at least onephotosensitive element sequentially senses a plurality of correctionsensing values when the projection device is projecting the presetcorrection images, and obtains a sensing correction function accordingto the correction sensing values, wherein the sensing correctionfunction is configured to convert actual sensing values of the at leastone photosensitive element into the first optical parameters and thesecond optical parameters.
 11. A projection positioning method,comprising: projecting, by a projection device, a first test image on aprojection screen based on a projection range, wherein the first testimage comprises a plurality of first image sub-zones and the first imagesub-zones respectively correspond to a plurality of first opticalparameters; dividing, in response to projecting the first test image bythe projection device, the first image sub-zone according to the firstimage sub-zone corresponding to one of the first optical parameterssensed by at least one photosensitive element, to generate a second testimage; projecting, by the projection device, the second test image onthe projection screen based on the projection range, wherein theprojection device projects the first test image and the second testimage at different time points, and the second test image comprises aplurality of second image sub-zones and the second image sub-zonesrespectively correspond to a plurality of second optical parameters;determining, in response to projecting the second test image by theprojection device, positioning information of the at least onephotosensitive element with respect to the projection range according tothe second image sub-zone corresponding to one of the second opticalparameters sensed by the at least one photosensitive element; andperforming a projection adjustment function according to the positioninginformation.
 12. The projection positioning method according to claim11, wherein the step of performing the projection adjustment functionaccording to the positioning information comprises: performing, by theprojection device according to the positioning information of the atleast one photosensitive element, projection within a specific enclosedrange surrounded by the at least one photosensitive element on theprojection screen, wherein the number of the at least one photosensitiveelement is greater than
 1. 13. The projection positioning methodaccording to claim 11, wherein the step of performing the projectionadjustment function according to the positioning information comprises:projecting, by the projection device, a specific totem on a position ofthe at least one photosensitive element according to the positioninginformation of the at least one photosensitive element.
 14. Theprojection positioning method according to claim 11, wherein sizes ofthe second image sub-zones are smaller than sizes of the first imagesub-zone.
 15. The projection positioning method according to claim 14,wherein the step of determining, in response to projecting the secondtest image by the projection device, the positioning information of theat least one photosensitive element with respect to the projection rangeaccording to the second image sub-zone corresponding to one of thesecond optical parameters sensed by the at least one photosensitiveelement comprises: determining, in response to determining that thesizes of the second image sub-zones conform to a minimum division unit,the positioning information of the at least one photosensitive elementwith respect to the projection range.
 16. The projection positioningmethod according to claim 11, wherein the first image sub-zones and thesecond image sub-zones are respectively arranged in a matrix, and thepositioning information comprises a first positioning position in afirst axial direction and a second positioning position in a secondaxial direction.
 17. The projection positioning method according toclaim 11, wherein the first optical parameters and the second opticalparameters comprise a color sensing value or a brightness sensing value,and the at least one photosensitive element comprises a color sensor ora brightness sensor.
 18. The projection positioning method according toclaim 11, wherein in response to projecting the first test image by theprojection device, one of the first image sub-zones overlaps the atleast one photosensitive element, and the at least one photosensitiveelement senses one of the first optical parameters corresponding to oneof the first image sub-zones.
 19. The projection positioning methodaccording to claim 11, wherein in response to projecting the second testimage by the projection device, one of the second image sub-zonesoverlaps the at least one photosensitive element, and the at least onephotosensitive element senses one of the second optical parameterscorresponding to one of the second image sub-zones; and the step ofdetermining the positioning information of the at least onephotosensitive element with respect to the projection range comprises:determining the positioning information of the at least onephotosensitive element with respect to the projection range according toposition information of one of the second image sub-zones in the secondtest image.
 20. The projection positioning method according to claim 11,further comprising: projecting, by the projection device, a plurality ofpreset correction images respectively corresponding to a plurality ofcolors; and sequentially sensing, by the at least one photosensitiveelement, a plurality of correction sensing values when the presetcorrection images are being projected, to obtain a sensing correctionfunction according to the correction sensing values, wherein the sensingcorrection function is configured to convert actual sensing values ofthe at least one photosensitive element into the first opticalparameters and the second optical parameters.